Printing foil attaching arrangement



May 24, 1960 w. RITZVERF'ELD ETAL 2,937,593

PRINTING FOIL ATTACHING ARRANGEMENT 6 Sheets-Sheet 1 Filed Feb. 25. 1957y 1960 w. RITZERFELD ET AL 2,937,593

PRINTING FOIL ATTACHING ARRANGEMENT Filed Feb. 25, 1957 6 Sheets-Sheet 2M y 2 1 w. RITIZERFELD ET AL 2,937,593

PRINTING FOIL ATTACHING ARRANGEMENT Filed Feb. 25, 1957 6 Sheets-Sheet 31 19.15 nglafiyrrfigzsfigzqF/gw 63 K n a N01 10/ 10/ f? May 24, 1960 w.RITZERFELD ETAL 2,937,593

PRINTING FOIL ATTACHING ARRANGEMENT 6 Sheets-Sheet 4 Filed Feb. 25, 1957jm entan' l7" z 4, 1960 RITZERFELD ETAL 2,937,593

PRINTING FOIL ATTACHING ARRANGEMENT Filed Feb. 25, 1957 6 Sheets-Sheet 5#7 .50 Z5 E r05 Q 9 my. a;

Drug/7102':

May 24, 1960 w. RITZERFELD ETAL PRINTING FOIL ATTACHING ARRANGEMENT 6Sheets-Sheet 6 Filed Feb. 25, 1957 2,931,593 PRINTING FOIL ATTACHINGARRANGEMENT Wilhelm Ritzerfeld, Schorlerner Alice 14, Berlin-Dahlem,Germany, and Gerhard Ritzerfeld, Franzenshader Str. 21,Berlin-Grunewald, Germany Filed Feb. 25, 1957, Ser. No. 642,003

Claims priority, application Germany Dec. 23, 1954 7 Claims. (Cl.fill-415.1)

The present invention relates to a printing foil attaching arrangement,and more particularly to an arrangement in which a thin flexibleprinting foil consisting of paper, of synthetic resin, of paper having ametal layer thereon, or consisting ofv metal is attached to the printingdrum of a duplicating apparatus.

This application is a continuation-in-part of patent application Ser.No. 553,342 filed December 15, 1955, en-

titleddTrinting Foil Attaching Arrangement, now abandone The knownattaching arrangements for lithographic printing foils us'e printingfoils provided with a series of perforations along the edge oftheprinting foil which are engaged by corresponding hook members on theprinting drum. The attaching arrangements of this type have the greatdisadvantage that very thin foils tear along the perforations thereof.

Other printing foil attaching arrangements are known in which theprinting foil is simply clamped to the printing drum. These arrangementshave the disadvantage that the inking rollers and moistening rollerswhich continuously run over the printing foil, frequently pull theprinting foil out of the clamping means.

It is the object of the present invention to overcome thesedisadvantages of the known attaching arrangements for printing foils,and toprovide a printing foil attaching arrangement by which theprinting foil is securely attached to the printing drum without beingtorn or without slipping out of the attaching means.

It is another object of the present invention to provide 'an attachingdevice for a printing foil provided with at least one projectingshoulder along at least one edge engaging the attaching device.

It is another object of the present invention to provide an attachingdevice for attaching a printing'foil in tensioned condition to thesurface of a printing drum.

It is a further object of the present invention to provide an attachingdevice for attaching a plurality of partly superimposed printing foilsto a printing drum.

Another object of the present invention is to provide a printing foilhaving a thickened edge portion along at least one edge thereof to format least one projecting shoulder along the edge.

It is also an object of the present invention to provide a sheetattaching arrangement for attaching a sheet having at least oneprojecting shoulder to a carrier member.

With these objects in view, the present invention mainly consists of asheet attaching arrangement which comprises, incombination, a carriermember having a surface formed with at least one elongated recessedshoulder; a sheet superimposed on the surface of the carrier member andhaving at least one elongated projecting shoulder engaging the recessedshoulder of the carrier member; and holding means secured to the carriermember and engaging the sheet for holding a projecting shoulder of thesame in engagement with a corresponding recessed shoulder of the carriermember. v According to another embodiment of the present inven- 7Patented May 24, 1960 tion a sheet is used which has at least along oneof its edges two projecting shoulders on opposite sides of the sheet,and the holding means are also provided with a recessed shoulder forholding the projecting shoulder on the side of the sheet'opposite tothat on which is located the shoulder that is held by the recessedshoulder of the carrier member. j

According to one embodiment of the present invention, the sheet is aprinting foil consisting of a thin flexible material, and thecarrier-member is a printing drum supporting the printing foil onthe'surface thereof.

.According to a preferred embodiment of the present invention, theprinting drum is provided with two recessed shoulders for holding aprinting foil having two projecting shoulders at the spaced edgesthereof. Preferably, one of the two recesses on theprinting drum isprovided in a movable member which is engaged by resilient means totension the printing foil on the surface of the printing drum.

Preferably, holding means are provided engaging the edge portion oftheprinting foil to hold the projecting shoulder of the printing foil inengagement with the recessed shoulder on .the drum.

In a modified embodiment of the present invention holding means areprovided for engaging with a recessed shoulder the projecting shoulderon the side of the sheet opposite to that on which is located theshoulder that is held in engagement with the recessed shoulder of thedrum. t

According to a modified embodiment of the present invention, the holdingmeans is provided with another recess for engaging a projecting shoulderon, anotherprinting foil, so that two printing foils may be partlysuperim posed on each other.

A printing foil according to the present invention is provided at leastalong one edge thereof with an edge por-' tion of increased thicknesswhich forms a projecting shoulder on one. side of the printing foil. Theedgeportion of increased thickness is preferably produced on theprinting foil by. bending upon itself the edge portion of the printingfoil at least once and preferably twice. I The bent over edge portionsare preferably adhesively, connected to each other and to the mainportionof the printing foil. A .water resistant glue is advantageouslyused for this purpose. It is, however, not absolutely necessary to gluethe turned over edge portionsof the printing foil to the main portion ofthe printing foil, since, the projecting edge portion of the printingfoil can be held by holding means in the recess of the printing drum.

According to a modified embodiment of the present invention a printingfoil is provided at least along. one edge thereof with an edge portionof increasedthickness which forms projecting shoulders on opposite sidesof .the printing foil. The edge portion of increased thickness ispreferably produced on the printing foil by bending upon itself the edgeportion of the printing foil atleast twice on one side and then aroundthe edge and at least once on the opposite side. The bent over edgeportions are preferably adhesively connected to each other and tothemain por tion of the printing foil. In certain cases, however, it may besufficient to bend the foil material without applying an adhesive.

Due to the fact that one or several thicknesses of the printing foilserve for holding the printing foil;'even very thin printing foilsconsisting of paper are reliablyheld even during along printingoperation. Particularly suited for attachment according to the presentinvention are printing foils consisting of paper provided with a metallayer. By the attachment means according-to the present invention it iswithout anyditliculty possible to use sheets of paper of standard size40g glued to a aluminum ing a thickness of'0.03-

The increased thickness of at least one edge portion of a printing foilmay also be obtained by attaching to the foil a strip of material onopposite sides of the edge portions so that these strips constituteprojecting shoulders on opposite sides of the foil. Instead of using twoseparate strips, one strip folded to U-shape may be used and the edgeportion of the foil inserted between the two legs of the U.

In order to prevent lateral slipping of printing foils according to thepresent invention whose length is. not exactly the same as the axiallength of the said recesses, it is advantageous to provide a pluralityof aligning members such as pins, projections, or similar membersengaging cutouts in the printing foil. These cutouts are not providedfor attaching the printing foil, but for the purpose of preventing thelateral slipping of the same. Con-. sequently, the cutouts extend incircumferential direction of the printing drum through a greaterdistance than the thickness of the holding pins or projections so thatonly the lateral sides of the projections engage the lateral edges ofthe cutouts and a slight movement of the printing foil incircumferential direction of the printing drum is possible foradjustment. The cutouts may be provided in the thickened edge portionsof the printing foil, but may also be provided in the main portion ofthe printing foil in the form of perforations. I

Instead of cutouts within the edge portion for the purpose set forthindentations spaced from each other extending from the edge of the edgeportion in circumferential direction of the printing drum may be usedwith the same effect.

This additional device is of particular value in the event that theorganization of the company using the device according to the presentinvention requires the use of printing foils of very different shapes onthe same machine. In the event that several printing foils are to beused in superimposed positions, it is also very useful to have theprinting foils aligned-by the aligning means according to the presentinvention so that no relative displacement between a plurality ofsuperimposed printing foils is possible.

The embodiment of the present invention in which not only one edge butboth edges of the printing foils are attached to the printing drum isparticularly advantageous when a great number of imprints have to betaken from a printing foil.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawings, inwhich:

Fig. 1 is a perspective view of a printing foil according to the presentinvention;

Fig. 2 is a side view of the printing foil illustrated in Fig. 1;

Fig. 3 is a side view of a modified printing foil according to thepresent invention;

Fig. 4 is a side view of another modified embodiment of a printing foilaccording to the present invention;

Fig. 5 is a side view of a further modified embodiment according to thepresent invention;

Fig. 6 is a perspective view of another modified embodiment of aprinting foil according to the present invention;

Fig. 7 is a fragmentary sectional view taken on line A--B in Fig. 6;

Fig. 7a is a fragmentary-sectional view of a modified embodiment of aprinting foil according to the present invention;

Fig. 8 is a fragmentary sectional view illustrating an embodiment of thesheet attaching means according to the present invention provided on aprinting drum; l

Fig. 9 is a fragmentary side view of the embodiment illustrated in Fig.8;

Fig. 10 is a fragmentary cross-sectional view of a modified embodimentaccording to the present invention taken on line A-B in Fig. 11;

Fig. 11 is a top view of the embodiment illustrated in Fig. 10;

Fig. 12 is a side view, partly in section of another modified embodimentaccording to the present invention, the section being taken on line A-Bof Fig. 13;

Fig. 13 is a fragmentary top view of the embodiment illustrated in Fig.12;

Fig. 14 is a fragmentary sectional view illustrating a detail of anothermodified embodiment according to the present invention;

Fig. 15 is a perspective view of a printing form foil having edgeportions of increased thickness so as to form shoulders projecting onboth sides;

Fig. 16 is a cross sectional side view of a foil composed of layers ofpaper and metal,,the edge portions thereof being reinforced by a stripof material enveloping the edge;

Fig. 17 is a cross sectional side view of a foil made of metal orsynthetic resin, the edge portions whereof are reinforced by a strip ofmaterial;

Fig. 18 is a cross sectional side view of the edge portions whereof arereinforced by two separate strips of material attached on opposite sidesof the foil;

Fig. 19 is a metal foil in cross sectional view, the edge portions beingreinforced by repeated bending back upon itself of the foil material;

Fig. 20 is a cross sectional side view of a foil composed of layers ofpaper and metal, the edge portions thereof being reinforced by attachingstrips of material to opposite sides of the foil and by an additionalstrip of material superimposed over said strips of material;

Fig. 21 is a plan view of a printing form foil provided withperforations in the edge portion of increased thickness;

Fig. 22 is a cross-sectional side view of the foil according to Fig. 21;

Fig. 23 is a plan view of a printing form foil provided withindentations in the reinforced edge portion;

Fig. 24 is a cross sectional side view of the printing form foilaccording to Fig. 23;

Fig. 25 is a transverse sectional view of a printing drum includingmeans for attaching a printing form foil;

Fig. 26 is a transverse sectional view of a printing drum includingmeans for attaching the forward and rear edge portions of the printingform foil;

Fig. 27 is a transverse sectional view of a printing drum includingmeans for attaching a printing form foil according to Fig. 21 andincluding additional means for engaging the cutouts thereof;

Fig. 28 is a transverse sectional view of a printing drum includingmeans for attaching a printing form foil according to Fig. 23 andincluding additional means for engaging the indentations thereof;

Fig. 29 is a plan view of a printing form foil with edge portionsprovided with projecting shoulders on both sides, said projectingshoulders being offset against each other;

Fig. 30 is a cross sectional side view of the printing form according toFig. 29;

Fig. 31 is a transverse sectional view of a printing drum includingmeans for holding a printing form according to Figs. 29 and 30 andincluding recessed shoulders offset against each other;

Fig. 32 is a top view of the printing drum according to Fig. 26; and

Fig. 33 is a transverse'sectional view of a printing drum includingseveral holding means for attaching to the drum several printing formsin superimposed position.

Referring to the drawings, and more particularly to Fig;

- pins or other suitable aligning means engaging the cuti, the printingfoil 1 is provided along one edge thereof with a portion of increasedthickness which is shown to be produced by bending upon itself the edgeportion of the printing foil 1.

As is best seen in Fig. 2, the edge portion 2 is first bent through anangle of 180 and then again bent through 180 to form a thickened edgeportion having a shoulder 3 projecting from one side of the printingfoil or sheet 1.

In the embodiment of Fig. 3, a strip Z' is glued to the printing foil 1,and thereupon the edge portion of the printing foil is bent upon itselfto envelop the strip 2'. Thereby a thicker projecting shoulder 3 isformed on one side of the printing foil. V

In the embodiment shown in Fig. 4 a strip 2' glued to the edge portionof the printing foil 1 to form a projecting shoulder 3.

In the embodiment of Fig. 5 the edge portion 2 of the printing foil 1 isbent to form an accordion pleat having a projecting shoulder 3.

In the embodiment of the printing foil illustrated in Fig. 6, the mainportion of the printing foil is provided with elongated cutouts or slots4 which extend in a direction transverse to the direction of the edge 3of the printing foil. As Fig. 7 shows, the elongated slots 4 are locatedin the main portion of the printing foil. In the embodiment illustratedin Fig. 7a, cutouts are provided in the thickened edge portion of theprinting foil.

The cutouts 4 are provided in the printing foil for the purpose ofengaging suitable pins or projections on the printing drum which engagethe lateral edges of the cutouts 4. Due to the elongated shape of thecutouts 4, a slight adjustment of the printing foil in a directiontransverse to the direction of the shoulder 3 is possible whereaslateral motions of the printing foil are prevented by outs 4. i

It will be understood that instead of slots in the thickened edgeportions or in the main portion of the sheet, open cutouts may beprovided along the outer-edge of the sheet and open on the outer edge ofthe sheet. By such cutouts an indented edge is formed along the sheetwhich permits the alignment of the sheet by suitable aligning means ormembers respectively engaging the open cutouts in the edge of theprinting foil as will be described hereinafter.

Figs. 8 and 9 illustrate a printing drum of a duplicating machineaccording to the present invention. The printing drum 5 rotates about orwith a shaft 6. In the cylindrical surface 7 of the printing drum 5 isprovided a recess 8 extending in axial direction of the printing drumand having a recessed shoulder -8' engaging the projecting shoulder 3 ofthe printing foil which is provided with a thickened edge portion.

The printing foil 1 is superimposed upon the surface of the printingdrum, and is subject to the pull exerted by inking rollers, moisteningrollers, and even by the counter pressure roller by which the copy sheetis pressed against the printing foil. Due to the fact that theprojecting shoulder 3 of the printing foil 1 engages the recessedshoulder 8' in the surface of the printing drum, a slipping of theprinting foil is impossible.

In order to prevent the thickened edge portion of the printing foil fromslipping out of the recess 8, holding means are provided for holding theedge portion of the printing foil in the recess 8.

The holding means include a holding portion located opposite the recess8 and being a part of a lever having an arm 9 to which a spring 11 isconnected. Due to the action of this spring 11 which is secured at theother end thereof to the printing drum, the lever 9 tends to turn into aposition in which its holding portion engages the thickened edge portionof the printing foil andreliably holdsthe same in the recess 8. A handlelever 10a .is. connected to the shaft 10 to which the lever 9 issecured. I By; manual operation .of. the handle 1012, the

holding means can be turned against the action of the spring 11 into aposition releasing the printing foil 1, and more particularly releasingthe edge portion 2 of the printing foil. Such a release is necessaryduring insertion anism does not project beyond the surface of theprinting.

drum. An interference of the holding means with the operation of thedrum is prevented by the fact that the recess '8 is not provideddirectly in the surface of the printing drum, but in the recessedsurface portion of the printing drum. Figs. 10 and 11 illustrate amodified embodiment of the present invention for holding on a printingdrum a sheet of the type as illustrated in Fig. 6. Pins 13 are providedon the printing drum and project through perforations 4 in the printingfoil 1. As described with reference to the embodiment of Figs. 8 and 9,a recess 8 is provided in a stepped recessed surface portion'of theprinting drum 5. The thickened edge portion 2 of the printing foil 1 isarranged in the recess 8 with the projecting shoulder 3 engagingtherecessed shoulder 8. As was explained with reference to Fig. 6, thepins 13, which constitute aligning means, are only provided for thepurpose of preventing lateral movement of the printing foil in axialdirection of the printing drum and permit slight adjustment of theprinting foil in circumferential direction of the drum. The holdingmeans is illustrated to be a lever 15 turnableabout a shaft 14, andurged by a spring 16 to engage the edge portion of the printing foil bya holding portion 15.

Figs. 12 and 13 illustrate a modified embodiment according to thepresent invention in which the printing foil 1 is secured at both endsthereof to the printing drum 5.

The thickened edge portion 2 of the printing foil engages with itsprojecting shoulder 3 the recessed shoulder 8 in the surface of theprinting drum. Holding means 9 are shown to be a lever pivotable about ashaft 10 and urged by a spring 7 to press the thickened edge portion Inorder to permit a slight tensioning of the printing foil 1, the otheredge portion of the printing foil is not positioned directly in a recessof the printing drum, but is located in a recess 20 provided in amovable member 18. The movable member-18 comprises a first element 18ahaving a recessed shoulder 26' and a second element 181) which isconnected by screws to member 18a. A spring 19 is connected at one endthereof to member 18a and at the other end thereof to the printing drumto urge the member 18 to slide in a direction transverse to the axialdirection of the printing drum. The thickened.

edge portion of the printing foil is located in the recess 26' formed bythe members 18a and 18b and engages with its projecting shoulder 3' therecessed shoulder 20' in the movable member 18. Consequently, the spring19 tensions the printing foil 1 by pulling its edge inwardly withrespect to the printing drum. 7

Holding means are provided forholding the thickened edge portion of theprinting foil in the recess 20, and

are illustrated to be a holding lever 21 turnable about a shaft 22 andbeing urged by the spring 23 into a position holding'the thickened edgeportion of the printing foil in the recess 20. As can be clearly seenfrom Figs. 12

and 13, the recessed shoulders 8' and 20' are separated from each otherat one side of the printing drum by a first surface portion of theprinting drum on which the printing foil 1 is superimposed at theother-side of the pr t r m by a econd. s f c po t n .of. her int nsdrum. The holding means 9 and 21 are located between the recesses 8 and20 at the other side of the printing drum. Due to the fact that thespring 19 produces a slight tension in the printing foil 1, theformation of folds is prevented in the foil.

Fig. 14 illustrates another embodiment according to the presentinvention which is adapted for attaching two partly superimposedprinting foils to the printing drum. The first printing foil 1 has againa thickened edge portion 2 located in a recess of the printing drum asdescribed with reference to the other embodiments of the presentinvention. A holding means 24 is provided for holding the edge portion 2of the first printing foil 1 in the recess 8. The holding means ispivotable about a shaft 25, and has a holding portion 24 which is formedwith another recess 27 having a recessed shoulder 27. A spring 26 urgesthe holding portion 24 of the holding means to the illustrated positionin which the first printing foil 1 is reliably retained in the recess 8.The second printing foil 29 has a thickened edge portion 28 forming aprojecting shoulder on the second printing foil 29, such projectingshoulder engaging the recessed shoulder 27 in the holding portion 24 ofthe holding means. Another holding lever 31 is provided for holding thethickened portion 28 of the second printing foil 29 in the recess 27. Aspring 33 urges the holding means 31 to turn about the shaft 32 and intothe holding position illustrated in Fig. 14. The arrangement illustratedin Fig. 14 is capable of attaching to the printing drum two printingfoils according to the present invention in superimposed position.

Fig. 15 is the illustration of a printing form foil 101 with one cornerbent over. In this particular embodiment the projecting shoulders alongthe two opposite end edges are formed by two strips of material 103formed to U-shape and attached adhesively to the edge of the foil.

Figs. 16 to are cross-sectional views illustrating different ways ofproviding a printing form foil with projecting shoulders along oppositeedges. In all these figures the numeral 101 designates the actualprinting form carrying reversed lettering for reproduction. In the caseof very thin foils a reinforcement is provided in the form of anattached layer 102 of paper or in the form of a covering consisting ofsynthetic resin.

Numeral 103 designates edge reinforcements formed by U-shaped strips ofmaterial, while in the embodiments of Figs. 18 and 20 separate strips104 are adhesively attached to the foil, said strips having a thicknessin the range between .1 and .2 mm.

In the embodiment according to Fig. 19 the reinforcement 105 is obtainedby repeated bending back upon itself the foil material and adhesivelyconnecting the folds with each other.

In order to locate a printing form in a predetermined relative positionin axial direction on the printing drum, the reinforced edge portion ofthe foil is provided with a set of cutouts, in this case elongated holes106, as shown by Figs. 21 and 28, which cutouts are adapted to beengaged by corresponding pins of a clamping device described furtherbelow.

In the embodiment according to Figs. 23 and 24, the cutouts for locationof the printing form in axial direction of the drum have the form ofindentations 107 adapted to engage corresponding projections in aclamping device described below.

Fig. 25 illustrates the way in which a printing form foil is attached toa printing drum, the means for attachment or clamping being shown insection. The body of the drum 108 forms with an edge portion 109 arecessed shoulder 112 which engages the projecting shoulder of theprinting form 101 on the lower side thereof. A holding means or clampinglever 110 is mounted for turning movement on the edge member 109 bymeans of an 'axle 113. The lever 110 is provided with a recessedshoulder 111 which engages the upper projecting shoulder of the printingform, the lever being urged into closing position by a spring 114. Sincethe printing form 101 abuts with its projecting shoulders formed by theU-shaped strip 103 against the 'two opposite recessed shoulders 111,112, the form is held in its position and' in engagement with theabove-mentioned shoulders by the tensile forces acting upon it in theoperation of the printing device.

. Fig. 26 illustrates a similar arrangement of the holding means asshown in Fig. 25, however, in this case the rearward edge of theprinting form is clamped by a second holding means or clamping leverwhich is acted upon by a spring:115.' A member 119 is arranged forsliding movement in a recess of the printing drum and is likewiseprovided with a recessed shoulder 112. A clamping lever 116 is mountedin the member 119 for turning movement about an axle 117 and is alsoprovided with a recessed shoulder 111, a spring 118 urging the lever 116into its closed position. The projecting shoulders of the U-shapedreinforcement of the printing form 101 engage the recessed shoulders 111and 112 of the holding means similarly as described above. The edgeportion of the foil is held by the springs in engagement with a holdingmeans and at the same time the form 101 is held stretched and snuglyagainst the cylindrical surface of the drum.

Fig. 27 illustrates holding means similar to those illustrated by Fig.26, however in this case pins 120, 121 are additionally provided forlocating the printing form in axial direction of the drum by means ofmutual engagement of said pins with the cutouts of the printing form asillustrated by Figs. 21 and 22. If the printing form is placed into theclamping arrangement in correct position the pins will only lightlytouch the lateral edges of the cutouts. If, however, the form ismislocated in axial direction of the drum, then the pins will engage thesurface of the edge portion of the form between said cutouts so that theclamping levers cannot be moved into their proper closed position onaccount of the interference between the pins and the edge portions.

Fig. 28 illustrates a similar clamping arrangement including, however,additional insert strips 122 and 123 which are formed so as to conformto the edge portions of the printing form illustrated by Figs. 23 and24. Also in this case the clamping levers cannot be closed unless theindentations of the printing form are properly lodged in relation to thecorresponding projections of the strips 122 and 123, respectively,whereby correct position of the printing form is assured.

In Figs. 29 and 30 a printing form is shown in plan view andcross-section. In this case the two legs of the U-shape of thereinforcing strip 103 are of different length so that the projectingshoulders 123 and 124 are located at different distances from the outeredge of the printing form, in other words, the projecting shoulders onopposite sides of the printing form are offset against each other.

Fig. 31 shows a printing drum in transverse section and provided withattachment means, the shoulders 111 and 112 so located that they areadapted to properly engage a printing form according to Figs. 29 and 30.

Fig. 32 serves to show a clamping arrangement according to Fig. 26 intop view so as to make it clear that the clamping device extends inaxial direction substantially over the whole width of the printing drum.

Fig. 33 shows a clamping arrangement specifically adapted for attachingboth a printing form 101 and a second form or cover sheet 125 which maybe used for covering certain portions of the printing form 101 which arenot to be reproduced when the printing device is operated. In this case,like in the preceding examples, the member 109 constitutes with the edgeof the drum 118 a recessed shoulder 112. A specially formed clampinglever 126 turnable around axle 113 is provided with the lever 126 intoclosed position. The reinforcement 103 of the printing form 101 abutswith its shoulders against the recessed shoulders 111 and 112. A secondclamping lever 130 is mounted on the lever 126 for turnable movementabout an axle 129 and is provided with a recessed shoulder 132, a spring131 urging the lever 130 into closed position. of the second form orcover 125 abuts with'its projecting shoulders against the recessedshoulder 132 of the lever 130 and the recessed shoulder 127 of the lever126, respectively. In this manner both the form 101 and the second formor cover 125 are safely attached'in proper position. i 1

For operating this clamping device one has to press first on the handle133 of the lever 130 which thereupon opens and first releases the formor cover 125, Where after the projections 126a and 130a engage eachother and cause the lever 126 to open so that now also the printing form101 can be removed from the clampingdevice. In a similar manner, theclamping devices are opened for inserting the printing forms.

It should be noted that projecting shoulders along an edge of a printingfrom can be obtained also by attaching separate strips of material alongsaid edge on both sides of the form and by enveloping said edge portionof increased thickness by a further strip shaped to U-form and attachedto said reinforced edge portion so as to envelop the latter.

With the attachment means according to the invention it is possible tohold firmly even extremely .thin printing form foils, for instance only.07 mm. thick paper and only .04 mm. thick paper attached to .03 mm.metal foil, and to run safely a practically unlimited number of copiesfrom such a form, for instance 25,000 pieces without trouble. This hasbeen quite impossible with known attachment means based on holes orperforations in the foil itself. The advantageous effect of theattachment means according to the invention is also caused by the factthat the projecting shoulder of the reinforced edge portion extendsuninterruptedly over the whole width of the form, i.e. in axialdirection of the printing drum.

' Since the projecting shoulders are provided on both sides of theprinting from in the case of certain embodiments of the invention, aparticularly uniform pull is exerted on both sides of the printing formso that 'it is not possible that the reinforced portion might tend totilt upwards which in extreme cases could possibly happen if there isonly a shoulder on one side of the form; besides, the pull being exertedon two shoulders on opposite sides of the printing form, each of the twoshoulders projecting on opposite sides of the edge portion of theprinting form has to carry only one-half of the total tensile load sothat tearing or separation of the reinforcing elements is safelyprevented. In fact, the attachment means 'according to the invention areso efiicient that attaching a printing form foil only with onereinforced edge to the drum is suitable for many thousand cycles ofoperation.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofsheet attaching devices differing from the types described above.

While the invention has been illustrated and described as embodied in asheet attaching device for holding on a printing drum a printing foilhaving at least one edge portion of increased thickness, it is notintended to be limited to the details shown, since various modificationsand structural changes maybe made without departing in any way from thespirit of the present invention. V Without further analysis, theforegoing will so fully reveal the gist'of the present inventionthatothers canby applying current knowledge readily adapt it for variousapplications without omitting features that, from the standpoint ofprior art, fairly constitute essential charactcristics of the generic orspecific aspects of this inven- The reinforcement 125a tionand,therefore, such adaptations should and are in tended to be comprehendedwithin the meaning and rangeof equivalence. of the following claims.

-What is claimed as new and desired to be secured b Letters Patent. is:

tion of said printingdrum and defining a first recessed shoulder on thesurface of the same; an elongated supporting member extending in axialdirection of said printing drum and being mounted on the same formovement in a direction transverse to the axis of said printing drum,said supporting member being formed with an elongated recess defining asecond recessed shoulder, said first and second recessed shoulders beingseparated from each other by a first surface portion of said printingdrum on one'side ofsaid printing drum and by a second surface portion onthe otherside of said printing drum; resilient means urging saidsupporting member to move in said transverse direction into a positionin which said first and second recessed shoulders are farther spaced incircumferential direction of said printing drum with respect tosaidifirst surface portion for tensioning a printing foil superimposedon said first surface portion of said print ing drum and having twoprojecting shoulders for respectively engaging said first and secondrecessed shoulders; two holding lever means mounted on said printingdrum on said other side of said printing drum between said recesses,said two holding lever means having holding portions respectivelylocated opposite said recesses in said printing drum and in saidsupporting member; and spring means engaging said two holding levers andurging the same into a position in which the respective hold ing portionof the same is located in the respective associated recess so as toslidably engage the printing foil of increased thickness definingoppositely projecting:

shoulders, one of said projecting shoulders engaging said recessedshoulder of said carrier member; and springloaded holding means securedto said carrier member and formed with a holding portion locatedopposite said supporting portion and with a second elongated recessedshoulder engaging the other one of said projecting shoulders, saidholding means resiliently and slidably abutting said elongatededge-portion for holding said sheet in a position in which saidprojecting shoulders of the same are in engagement with said first andsecond recessed shoulders of said carrier member and of said holdingmeans, respectively, and permitting sliding of said sheet into saidposition.

3. Printing foil attaching arrangement comprising, in combination, aprinting drum having a surface formed with two axially extending andcircumferentially spaced supporting portions and an elongated recessextending along each of said supporting portions, each of said recessesdefining a recessed shoulder in said surface of said a printing drum; aprinting foil superimposed on said surface of said printing drum andhaving two parallel edge portions of increased thickness, said edgeportions defining elongated projecting shoulders on opposite sides ofsaid printing foil, one of the projecting shoulders of each of said edgeportions being at least partly located in one of saidrecesse's',-respectively, of said printing drum with said projectingshoulders engaging said recessed shoulders; and two spring-loadedholding means secured to said printing drum and having each a holdingportion opposite said supporting portions and an elongated recess alongthe respective holding portion thereof, said elongated recesses of saidholding means defining second recessed shoulders engaging respectivelythe other ones of the projecting shoulders of each of said edge portionsof said printing foil on the other side thereof, said holding meansresiliently and slidably abutting said edge portions for holding saidedge portions in a position in which said projecting shoulders of saidprinting drum and of said holding means, respectively, are in engagementwith said projecting shoulders of each of saidtwo parallel edge portionsof said printing foil and permitting sliding of said foil into saidposition.

4., Printing foil attaching arrangement comprising, in combination, aprinting drum having a surface including a surface portion formedwith atleast one supporting portion and with one recess extending along saidsupporting portion and defining in said surface portion a recessedshoulder extending in axial direction; a thin flexible print ing foilsuperimposed on said surface of said printing drum and on said surfaceportion thereof and having at least one elongated edge portion ofincreased thickness defining projecting shoulders on opposite sidesthereof, one of said projecting shoulders being at least partly locatedin said recess of said printing drum with one of said projectingshoulders engaging said recessed shoulder, said printing foil beingformed with a set of cutouts passing through said edge portion and beingspaced from each other along the length of the same in said axialdirection, said cutouts extending transversely to said axial direction;a set of aligning members secured to said printing drum and projectingfrom the surface of the same, said aligning members being spaced fromeach other in axial direction of said printing drum and passing throughsaid cutouts of said edge portions to secure said printing foil againstmovement in axial direction; and spring-loaded holding means secured tosaid printing drum and including a holding portion located opposite saidsupporting portion and being formed with .a recess extending along saidholding portion and. resiliently and slidably engaging on the other sideof said printing foil one of said shoulders projecting on said otherside of said printing foil for holding said edge portion in a positionin which said projecting shoulders of said printing foil are inengagement with said recessed shoulders of said printing drum and ofsaid holding means and for permitting sliding of said foil into saidposition, while said cutouts are in substantial alignment with saidaligning members.

5. Printing foil attaching arrangement comprising, in combination, aprinting member having a surface formed. with at least one recess havinga recessed shoulder transverse to said surface; a printing foilsuperimposed on said surface of said printing member and having at leastone thicker edge portion defining at least one transversely projectingshoulder on at least one side of said printing foil, said thicker edgeportion being at least partly located in said recess of said printingmember with said projecting shoulder abutting said recessed shoulder;and holding means including a holding member mounted on said printingmember for movement transverse to said printing foil and having aholding face slidably engaging said edge portion of said printing foilon the other side of said printing foil, and spring means on saidprinting member urging said holding member to move transversely withsaid holding face against said edge portion for holding said edgeportion in said recess of said printing member while permitting slidingof said foil on said surface until said shoulders abut each other.

6. Printing foil attaching arrangement comprising, in combination, aprinting member having a surface formed with at least one recess havinga recessed shoulder transverse to said surface and a slide face adjacentsaid shoulder; a printing'foil superimposed on said surface of saidprinting member and having at least one thicker edge portion defining atleast one transversely projecting shoulder on at least one side of saidprinting foil and another slide face adjacent said projecting shoulder,said thicker edge portion being at least partly located in said recessof said printing member with said projecting shoulder abutting saidrecessed shoulder and with said slide faces slidably engaging eachother; and holding means ineluding a holding member mounted on saidprinting member for movement transverse to said printing foil and tosaid slide faces and having a holding face slidably engaging said edgeportion of said printing foil on the other side of said printing foil,and spring means on said printing member urging s'aid holding member tomove transversely with said holding face against said edge portion forholding said edge portion in said recess of said printing member whilepermitting sliding of said foil on said surface until said shouldersabut each other.

7. Printing foil attaching arrangement comprising, in combination, aprinting member having a surface formed with at least one recess havinga recessed shoulder transverse to said surface and a slide face adjacentsaid shoulder; a printing foil superimposed on said surface of saidprinting member and having at least one thicker edge portion defining atleast one transversely projecting shoulder on at least one side of saidprinting foil, said thicker edge portion being at least partly locatedin said recess of said printing member with said projecting shoulderabutting said recessed shoulder; and holding means including a holdingmember mounted on said printing member for turning movement about anaxis parallel to said shoulders, said holding member having a portionmoving transverse to said printing'foil and having a holding faceslidably engaging said edge portion of said printing foil on the otherside of said printing foil, and spring means on said printing memberurging said holding member to move transversely with said holding faceagainst said edge portion for holding said edge portion in said recessof said printing member while permitting sliding of said foil on saidsurface until said shoulders abut each other.

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